Print head shift mechanism



1970 L. J. KAPP PRINT HEAD SHIFT; MECHANISM Original Filed Dec. 16, 19666 Shee ts-Shee t 1 Nl/EN 0 ZUDW/c; J. 164 PP Feb. 3, 1970 L. J. KAPPPRINT HEAD SHIP '1 MECHANISM 6 Sheets-Sheet 2 Original Filed Dec.

lNl ENTOR J KAPP Feb, 3., 1970 L. .LKAPP 3,493,091

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' PRINTHEAD SHIFT MECHANISM Original Filed Dec. 16, 1966 6 shets-sheet 4JIIL] INVENTOR [Hall/l6 J- #41910 Feb. 3., 1970 Qriginal Filed '49 FIG.6

PRINT HEAD SHIFT MECHANISM Dec. 16, 1965 L. J. Km 3,493,091

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l l INVENTOR Feb. 3, 1970 L. J.:KAPP

FRINTflEAD SHIFT MECHANISM Original Filed Dec.

6 Sheets-Sheet 6 ZERO DEFL.

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IN VENTOR L UDV/G J. K APP MASTER CONTROL United States Patent Int. Cl.B41j 25/24, 1/32 US. Cl. 197-71 11 Claims ABSTRACT OF THE DISCLOSURE Amechanism which is operable to shift the elevation of a print head sothat one of the twotype bands thereon will be moved into printingposition. A pivoted arm is connected to a vertical shaft on which theprint head is positioned.

The arm is pivoted to a raised or lowered position to bring one or theother of the two type bands into printing position by actuating eitherone of the two opposed solenoids located above and below the arm and onone side of the point at which it is pivoted. Acting together with thesolenoids are two opposed springs which are connected to the other sideof the pivot point. These springs are positioned so that when the arm isshifted from one position to the other by actuation of a solenoid, thespring opposite thereto will be stretched to store energy therein sothat when the other solenoid is actuated, it will act together with thatsolenoid to bias the arm and thereby the print head to its new position.

This application is a division of application Ser. No. 603,330, filedDec. 16, 1966, invented by Ludwig I. Kapp, and entitled Reed OperatedPrinter.

BACKGROUND OF THE INVENTION The invention relates to an improvement inprinting mechanisms, and particularly to a novel means for shifting aprint head so that one or the other of two type bands thereon is movedinto operative printing position.

Prior art devices relied on a single mechanism to actuate an arm toraise and lower a type member between one of two printing positions.Solenoids and other such mechanisms were often employed, but since onlyone mechanism was used, the fatigue on this mechanism through constantoperation would eventually result in its failure.

Applicant, on the other hand, has provided springs which work inconjunction with solenoids so that the longevity of the solenoids, andtherefore the entire mechanism, will be significantly increased.

SUMMARY OF THE INVENTION A print head shifting mechanism is providedwhich comprises opposed solenoids working in conjunction with opposedsprings for biasing an arm and thereby a print head which isinterconnected thereto between first and second printing positions. Asone solenoid is actuated, its opposed spring is stretched so that energyis stored therein. Then when the other solenoid is actuated, and thefirst solenoid is released, the energy in the spring acts to bias thearm and the print head to its new position.

BRIEF DESCRIPTION OF THE DRAWINGS FIGS. 1-1A jointly show a frontelevation of the machine embodying the invention.

FIG. 2 is a left side elevational view of the machine.

FIG. 3 is a plan view of the power reed and associated magnets as viewedalong line 33 of FIG. 2.

FIG. 4 is a right side elevation of the printing unit.

FIG. 5 is a top sectional view taken along the line 5-5 of FIG. 4.

3,493,091 Patented Feb. 3, 1970 'FIG. 6 is a plan view of the printingunit.

FIG. 7 is a cross section elevation of the same taken on line 7-7 ofFIG. 6.

FIG. 8 is an enlarged fragmentary plan view of the printing drum andaligner means therefor.

FIGS. 99A and 10 are graphic illustrations of an operation of the powerdevice.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now in particular toFIGS. 1-1A, the machine embodying the present invention comprises leftand right side frames 1 and 2 having supported for rotation therein anon-shiftable work support platen 3. Forwardly within said frames issecured a transverse rod 4, while rearwardly of rod 4 said framessupport a rail 5, which together serve to support for transversemovement a shiftable carriage C having mounted thereon the characterprinting drum 6, as hereinafter described.

Secured to the left side of said carriage by means of stud 7 is aflexible steel tape 8 which passes first around a pully wheel 9pivotally mounted upon a bracket 10 fast to the left side frame 1, thenacross the front of the machine and around a pully wheel 11 rotatablysupported upon bracket 12 secured to the right side frame 2, andsubsequently is wound upon the drum 13 fast to the shaft 14 of astepping motor 15. Fast also to motor shaft 14 is a second drum 16 onwhich is wound a similar tape 17, which passes around a pulley wheel 18and is secured to the right side of the printing carriage C by means ofstud 19. Thus in accordance with certain selective impulse signals, asreceived from any suitable control source or computer means in thewell-known manner, motor 15 serves to displace printing carriage Cselective distances either to the right or to the left.

Printing carriage C comprises a support frame 20 (FIGS. 4-7) the forwardend of which. is slidable upon the rod 4 and the rearward end havingrollers 21 for riding along the rail 5. Frame 20 is provided with a pairof upwardly extending trunnions 22 for receiving the pivot studs 23 fastwithin the bifurcated arms 24 forming the lower end of a U-shaped frame24. Within the upper arm 24" of said frame is bearinged for rotation theupper portion of a shaft 25 upon which is fast the character or printingdrum 6. If desired, drum 6 and shaft 25 may be a single piece, forinstance, of molded nylon material. The lower end of shaft 25 isenlarged to form a socket for receiving the ball-shaped end 26 of ashaft 27 extending upwardly from a stepping motor 28 supported to theunderside of the printing carriage frame 20. A pin 29 extends throughball 26 and is received by an elongated vertical slot 30 in the lowerend of the printing drum shaft 25, whereby to effect drive connectionthereof with the motor shaft 27 in manner to permit an upward anddownward movement of the printing drum.

To efiect upward and downward movement of the printing drum, a pair ofspaced rearwardly extending levers 31 are each pivotally mounted at 32upon an upwardly extending portion 20' of the carriage frame 20. Therearward ends of each lever 31 are bifurcated to embrace the top andbottom sides of an enlarged circular disc 33, comprising a shoulder onthe shaft 25. Mounted to extend between the pair of arms 31 for movementtherewith, is a metal block 34 which said arms serve as an armaturebetween two opposed magnets 35, 36 supported upon the frame portion 20'of the printing carriage C. With both said magnets in their deenergizedcondition, a pair of balanced springs 37-37 will act to hold levers 31and thereby the printing drum 6 at substantially a midpoint positionrelative to bringing one or the other of two rows of printing charactersarranged around the circumference of drum 6 to the printing line withrespect to platen 3. It is intended, however, that either magnet shallremain normally energized in accordance with any previous final impulsesignal transmitted thereto from the known input devices.

It will be apparent from the above, therefore, that upon simultaneouslydeenergizing either one of said magnets while energizing the other inaccordance with a selected impulse signal, armature 34 will move eitherupwardly or downwardly until stopped by the particular magnet thatbecomes energized. Thus the lever 31 is rocked either clockwise orcounterclockwise about point 32 in accordance with such impulse signals,and will raise or lower shaft with printing head 6 to selectively bringeither row of printing characters thereon into printing alignment withthe work support platen 3.

It will be noted that in such operations, potential energy provided inone of the opposed springs 37-37 will decrease while that of the otherspring will increase, with the result that lever 31 with armature 34 iscaused to be spring biased for either direction of its movement.

This arrangement of spring balancing and with providing caps 38 ofsuitable anti-magnetic material, such as tetrafluoroethylene, commonlyknown as Teflon, upon the core of each magnet serves to provide for amore rapid response of the above devices to any said input impulsesignals thereto.

A selection of any desired character to be printed is effected throughselective forward or reverse operations of stepping motor 28 to adjustdrum 6 from any last previous character selection position to any othercharacter position according to the particular input signals receivedthereto from the master control devices.

The novel means for effecting a fore and aft printing stroke movement ofthe printing character drum 6 will now be described.

Rotatably mounted upon a pair of spaced studs 40, 41 fast to the frame20 of the shiftable carriage C are pulley wheels 42, 43, respectively.Guided between the trunnion arms 22 supporting the pivoted rock frame24, upon which is mounted the printing drum 6, is a slide block 44having a pair of spaced shoulders 45, 46 extending rearwardly ofcooperating spaced arms 47, 48 depending downwardly from said rock frame24. An elongated notch 49 in block 44 permits said block to straddle themotor shaft 27, while a rod 50, mounted between the shoulders 45, 46 hasone end of a spring 51 secured thereto. The other end of spring 51 issecured to a stud 52 fast within frame 20 and serves to bias block 44rearwardly. A pair of springs 61, each at one end, being connected tothe related arm 47, 48, respectively, and at their other end to a rod62, held in a suitable notch in the rearward face of shoulders 45, 46,serves to yieldably bias said arms against the forward surface of saidshoulders. The forward end of block 44 is bifurcated to form upper andlower bearing support for a shaft 53 upon which is mounted for rotationbetween said supports a pulley wheel 54.

With reference to FIGS. 1-lA, a flexible steel tape 55 is secured bystud 56 to the fixed bracket 12 of the machine and extends leftwardly,around the forward surface of pulley wheel 43, thereafter rearwardlyaround the pulley 54, forwardly around pulley 42 and again leftwardly topass around a stationary pulley 57 and thence is secured at its oppositeend to the distal end of a resilient reed 58 (FIGS. 2 and 3), having theopposite end thereof fast to the base plate 59'. Said reed comprises thearmature member for a pair of parallel electromagnets 60 fast to thebase plate 59, and is designed to effect a printing operation of thedrum in the following manner.

Assuming power has been turned on in the machine with the result thatmagnets 60 are thus energized, reed 58 is now deflected and held by saidmagnets so that tape 55 will be in a released condition. This permitsspring 4 51 to hold slide block 44 with pulley 54 in a rearwardposition, thereby taking up any slack which would be imparted to tape 55by said deflection of reed 58. At this time, springs 61 will cause frame24 with printing head 6 to be held in a counterclockwise position.

Magnets 60 may thereafter be deenergized and reenergized according to anestablished impulse repetition rate as transmitted thereto from anywell-known control devices. So that any residual magnetism in magnets 60will not delay a release of the reed 58, the side of said reed towardsmagnets 60 is covered with a suitable antimagnetic substance, such asfor instance, tetrafluoroethylene and known commonly under the nameTeflon. Upon a deenergizing of magnets 60, reed 58 is released and willimpart a leftward movement (FIG. 1) to the tape 55. The opposite end oftape 55 being held, as earlier described, it will be obvious that pulley54 will be moved forwardly, being leftwardly as shown in FIGS. 5 and 6,and will move slide block 44 therewith to impart thereby a rapidclockwise rotation to the frame 24 and printing head 6. During suchoperation, reed 58 reaches its maximum velocity and will then deceleratein characteristic manner. However, tape 55 will only pull slide block 44partly forward, whereafter acceleration imparted thereby to frame 24 andprinting head 6 will cause the printing head to continue onward andstrike the usual type ribbon 63 for printing upon any record form asinterposed between said ribbon and the support platen 3. During thislatter portion of the printing stroke, it is noted that the decelerationof reed 58- slows motion of slide block 44 and the printing head ispermitted to strike freely, so that no printing impact is transmittedback to the tape, thereby avoiding damage to the tape.

On the return stroke of the oscillation of reed 58, tape '55 is causedto be relaxed, permitting spring 51 to return slide block 44 rearwardly,while springs 61, as aided by rebound of the parts and by increasedenergy stored therein during the printing stroke, restores frame 24 andprinting head 6 counterclockwise to normal position.

From the above therefore, it will be noted that because reed 58 actslike a leaf spring, it tends to resonate but is restricted to one cycle,that is, it leaves the magnets 60 as said magents are deenergized andpulls tape 55 on a forward stroke, or away from the magnets. On thereturn stroke of the reed 58, in completing the cycle, said reed isrecaptured by magnets 60 when energized, as hereinafter described, by acontrol circuit applied to said magnets at a given time before the reedhas fully returned and which builds up the magnetic field sufficientlyto pull reed 58 a remaining short distance to normal, whereby theassociated parts operated by tape 55 also return to normal, with aminimum of chatter or rebound.

To further understand certain operations and advantages of applicantsnovel devices, reference is made to the graphic illustrations shown inFIGS. 9, 9A and 10, which will now be described.

FIG. 9 illustrates the force applied by magnets 60 for deflecting powerreed 58 incident to an initial potential energy storing stroke for saidreed and as related to the required force of said magnets for anysubsequent deflections of the reed.

Assuming at the start that all power is off, the reed 58 would then haveno deflection, as illustrated at ZERO DEFL. on the x coordinate. Aninitial momentary high current force of a magnitude to saturate magnets60 for deflecting reed 58 sufliciently to close the initial gap G may beinduced incident to the turning on of power or in any other suitablemanner and is illustrated by the high current force line, which it willbe noted is throughout always above or greater to the force line Rrepresenting the deflection requirement of reed 58. Immediatelysubsequent to the high current maximum force, indicated at F on the yaxis, it is intended that maximum magnetic force on the magnets shalldrop to a point P on the chart.

This reduced force, however, will maintain said magnets energizedsuflicient to hold reed 58 at its maximum deflection point +D.Thereafter, at any time, magnet 60 is caused to be deenergized reed 58being released and by virtue of its inbuilt potential energy will moveat its natural resonance to the point D and immediately back to a point+D as indicated by broken lines on the chart. At said point suitablewell-known circuit control means, which include a one shot multivibratorOSM (FIG. 9A) will function to reenergize magnets 60, whereupon saidmagnets complete the final gap closing movement of reed 58 to themagnet, as represented by the solid line from point +D to point +D onthe chart. Now from the above and by observation of the chart, it willbe noticed that the low current magnetic force curve will intercept theforce line R, requirement for the reed at substantially the line +D andwill fall below the designed reed force R along a substantial portion ofsaid line R. Thus the kinetic energy of the moving reed is beingutilized during this time portion, and a reduced power is thereforepossible for magnets 60 to return reed 58 the remaining short gaprepresented by line +D' to +D and restore full potential energy to saidreed. Also, more latitude is permissible in the timing for reenergizingof said magnet.

FIG. is a sinusoidal wave chart, relating the velocity curve of the reed58 with a time displacement curve thereof and indicating the manner inwhich the reed becomes self-cushioning in the printing oscillationthereof and how the shock, earlier described, is minimized in theoperations of the reed. Also, FIG. 10 with FIG. 9A illustrates how thereed power means functions to operate the printing devices in a giventime sequence with any input repetition rate from the master controldevices.

Assuming that the magnet 60 is now energized, reed 58 will be held bysaid magnets at its maximum potential nergy shown at +D on the ycoordinate. The reed being stationary is so illustrated at zero velocity(ZERO VEL.) on the conjunction of coordinates xy. Upon release of reed58 following a deenergizing of magnet 60, the reed advances to zerodeflection point A on the reed displacement curve. At this time, thereed has attained maximum velocity as indicated on the velocity curve.Reed 58 now reverses its force as it moves beyond point A to point Dduring which the velocity curve will again go to zero. However it willbe recalled that the printing head 6 will continue in its forwardprinting stroke movement to effect a printing during this periodmovement of reed 58. Returning now from point -D the reed curverecrosses the x axis at return maximum velocity and its force again isreversed in going to the point +D' at which point velocity will again bezero and all kinetic energy has now been translated to potential energyin reed 58.

It is recalled that at +D' reed 58 is not as yet fully returned to themagnets 60, indicated at point +D on the graphs. At this time, asearlier set forth, suitable one shot multivibrator time delay circuitmeans OSM (FIG. 9A) well-known to the art, will cause a reenergizing ofmagnets 60 to complete the deflection of reed 58 from point +D' to point+D. It will be noted from the velocity curve that during this shortmovement and time period the velocity of reed 58 produced by magnets 60is so low that very little impact occurs as reed 59 strikes magnets 60and thereby avoids noise and shock, with a possible breaking occurringto the tape 55.

Since any buildup time required in energizing magnets 60 are known, itof course, is possible to time its energizing action slightly early tothe point +D on the chart.

From the above description, it will be apparent that during anyrepetitious incoming signals spaced at a predetermined time interval, asfrom any suitable master control machine, magnets 60 are caused to bedeenergized each time for releasing a power reed 58 to effect by saidreed successive printing operations and that said magnets are timed byknown circuit control devices to be reenergized in a timed sequence withsuch input signals so as to complete the restoring of potential energyagain within reed 58 in corresponding time for each subsequent releasethereof.

Suitable well-known feed back circuits, not herein deemed necessary toset forth, may be included where required to control timing starts forany input signal to the printer from the master control means.

While there has been shown a preferred embodiment of the invention, itwill be understood that various changes may be made in the form, detail,arrangement and proportions of the parts without departing from thespirit and scope of the invention. Accordingly, it is intended that theforegoing disclosure be illustrative only and not limitative of thefollowing claims.

I claim:

1. A printing mechanism comprising a print head having first and second]rows of indicia thereon alternatively alignable with a printingposition;

a shaft mounted for sliding, rotational and tilting motion on which saidhead is mounted;

an arm mounted about an axis, said arm having first and second sides;

means coupling said arm to said shaft for permitting relative tilting,rotational and sliding motion between said arm and said shaft;

said arm engaging said shaft to shift said shaft and thereby said printhead to a first position wherein a first set of indicia is aligned withthe printing position and a second position wherein the second set ofindicia is aligned with the printing position;

a first electromagnetic means positioned adjacent to said arm andadapted to move said arm about said axis;

a second electromagnetic means positioned adjacent to said second sideof said arm and adapted to move said arm about said axis;

spring means biasing said arm to midpoint position between said firstand second electromagnetic means and adapted to have potential energystored therein upon movement of said arm;

said spring means coacting with said first means to release potentialenergy stored in the spring to cause movement of said arm about saidaxis to thereby cause said print head to move between said firstposition and said second position.

2. The mechanism of claim 1 wherein second spring means is provided,which spring means is connected to said arm adjacent said second sidethereof, and wherein said second spring means is adapted to havepotential energy stored therein upon movement of said arm, and whereinsaid second spring means coacts with said second electromagnetic meansto release the potential energy stored in the spring to cause movementof said arm about said axis and thereby cause the print head to movebetween said second position and said first position.

3. The mechanism of claim 2 wherein said arm has a first end and asecond end, said first end being proximal to said printing head and saidsecond end being distal to said printing head; and

wherein said axis is positioned between said first and second ends andbetween said first and second sides.

4. The mechanism of claim 3 wherein said first electromagnetic means ispositioned adjacent said first side of said arm and between said axisand first end, and wherein said second electromagnetic means ispositioned adjacent said second side and between said axis and saidfirst end.

5. The mechanism of claim 4 wherein said first and second spring meansare connected to said arm between said axis and said second end.

6. The mechanism of claim 5 wherein said first and secondelectromagnetic means comprise electromagnets which are adapted to beenergized and deenergized and wherein said first spring means and saidsecond biasing means comprise tension springs.

7. The mechanism of claim 6 wherein said arm is horizontally disposedand said electromagnets are disposed substantially perpendicular to saidarm and said springs are positioned substantially perpendicular to saidarm.

8. The mechanism of claim 7 wherein said electromagnetic means comprisesolenoids.

9. The mechanism of claim 8 wherein said print head comprises a circulardisc, and

wherein said first and second set of indicia comprises parallel bands ofprint symbols.

10. The mechanism of claim 9 wherein:

a shoulder is provided on said shaft, which shoulder is engaged by saidarm to interconnect the arm and the print head.

11. The mechanism of claim 6, said shoulder being a flat projectingmember having a first and second surface and being positioned in a planeperpendicular to said shaft, said arm having a first and second springfinger projecting therefrom, said shoulder being engaged between saidspring fingers so that said first surface is engaged by the first springfinger and said second surface is engaged by said second spring finger,whereby said shoulder and said shaft are adapted to tiltably move in anarc, to slideably move vertically and to move rotationally while beingengaged by said fingers.

References Cited UNITED STATES PATENTS 1,736,683 11/1929 Wakeland335-181 2,633,488 3/1953 Brion 335274 XR 485,761 11/1892 Heiss 197-121,083,076 12/1913 Fischer 197-12 1,355,089 10/1920 Clark -2 197-121,936,656 11/1933 Bell 178-34 2,029,957 2/1936 Trachtenberg 197123,286,806 11/1966 Schoenfelder 197-55 XR 3,291,041 12/1966 Burchfield eta]. 19755 XR EDGAR S. BURR, Primary Examiner US. Cl. X.R. 197--55

